Combination tube form bend and inflation application

ABSTRACT

A METAL STRIP HAVING AT LEAST ONE INFLATABLE FLUID PASSAGEWAY SANDWICHED WITHIN IT AND CONTAINING AT LEAST ONE GROOVE IN SUBSTANTIAL CORRESPONDENCE TO THE INFLATABLE PASSAGEWAY EXTENDING INTERMEDIATE THE ENDS OF THE STRIP. THE GROOVE IS IN THE BEND AREA OF THE STRIP. PREFERABLY THE STRIP IS BENT IN THE BEND AREA AT LEAST 25* AND THE BEND RADIUS IS LESS THAN 1 INCH. IN THE MOST PREFERRED EMBODIMENT THE INFLATABLE PASSAGEWAY CORRESPONDS TO A PATTERN OF STOP-WELD MATERIAL.

R. A. SHIVE Oct. 10, 1972 COMBINATION TUBE FORM BEND AND INFLATIONAPPLICATION 3 Sheets-Sheet 1 Original Filed Feb. 26, 1969 INVENTORR/CHARD A. SH/VE ATTORNEY R. A. SHIVE Oct. 10, 1972 COMBINATION TUBEFORM BEND AND INFLATION APPLICATION Original Filed Feb. 26, 1969 5Sheets-Sheet 2 M ww INVENTOR RICHARD A. SH/VE ATTORNEY R. A. SHIVE Oct.10, 1972 COMBINATION TUBE FORM BEND AND INFLATION APPLICATION 3Sheets-Sheet 3 Original Filed Feb. 26, 1969 INVENTOR I R/CHAPD A. SH/VEZ4. W film ATTORNEY United States Patent Oflice 3,697,236 Patented Oct.10, 1972 3,697,236 COMBINATION TUBE FORM BEND AND INFLATION APPLICATIONRichard A. Shive, Alton, Ill., assignor to Olin Corporation Originalapplication Feb. 26, 1969, Ser. No. 823,220, now abandoned, which is adivision of application Ser. No. 709,636, Mar. 1, 1968, now Patent No.3,545,394. Divided and this application Aug. 13, 1970, Ser. No.

Int. Cl. B21c 37/02; B21d 11/20 US. Cl. 29-191 Claims ABSTRACT OF THEDISCLOSURE A metal strip having at least one inflatable fluid passagewaysandwiched within it and containing at least one groove in substantialcorrespondence to the inflatable passageway extending intermediate theends of the strip. The groove is in the bend area of the strip.Preferably the strip is bent in the bend area at least 25 and the bendradius is less than 1 inch. In the most preferred embodiment theinflatable passageway corresponds to a pattern of stop-weld material.

This application is a division of copending application Ser. No.823,220, filed Feb. 26, 1969, now abandoned, which in turn is a divisionof application Ser. No. 709,636, filed Mar. 1, 1968, now Pat. No.3,545,394.

This invention relates to processing metal strip containing st0p-weldmaterial which strip is to be subsequently inflated to form passageways.However, this invention could be practiced on flat seam weldedpassageways or flattened seam, or seamless tubing shipped in coil form,either of which to be inflated after shipping.

It is well known to place a pattern of stop-weld material on one sheetand then by appropriate processing bond the sheet containing thestop-weld material to at least one other sheet at all places exceptWhere the stop-weld has been placed. After the bonding, the passagewaypattern defined by the stop-weld material may be inflated to formpassageways.

It is often convenient to inflate such passageways in strip material andto bend the strip material into long serpentine shaped structures whichhave heat exchange application.

However, if a radius below approximately one inch is bent, their resultskinking in the inside radii of the tube and a reduction in tube heighton the outside radii of the tube is evident. This is generally the casein tube wall thicknesses less than 0.030 inch. Kinking isdisadvantageous because if the expanded passageways contain kinks, ahigher pressure drop occurs.

Furthermore, the kinking may be sufiiciently severe to cause failures inthe material. For instance, for condenser applications pressures up to3,000 p.s.i. must be tolerated in the passageways. Evaporator orpressures up to 1,200 p.s.i., msut be tolerated.

Thus, it is an object of the present invention to avoid kinking whichoften occurs during bending in a conventional fashion.

It is another object of the present invention to avoid kinking whenbending strip at a radius of less than one inch.

It is another object of this invention to emboss and bend tube wallthicknesses below 0.030 inch without kinking.

It is another object of the present invention to provide a method andapparatus for bending strip to be used in serpentine shaped heatexchangers.

It is another object of this invention to provide a method of bendingstrip whereby fin material can be placed between the bent strip and theninflated to form heat exchangers.

Other objects will be apparent from the following descriptions anddrawings.

FIG. 1 is a schematic perspective view of the apparatus and process ofthe present invention.

FIG. 2 is a sectional view of the center spindle assembly which is usedin the apparatus of the present invention.

FIG. 3 is a perspective view of the movable base plate and dividerblocks.

FIG. 4 is a perspective view of the roller assembly.

FIG. 5 is a perspective view of the follower block and pins which may beutilized in the present invention.

FIG. 6 is a perspective view of strip material which has been bent andformed according to the present invention.

FIG. 7 is a perspective view of strip which has been bent according tothe present invention, fin material placed between the strip, and thestrip inflated to form a heat exchanger.

'FIG. 8 is a schematic view of an exemplary process sequence which maybe utilized according to the present invention.

In FIG. 1 there is shown a fixed base plate 10 upon which is mounted amovable base plate 20. Passing through the movable base plate is acenter spindle 30. As shown in FIG. 2, this center spindle has anenlarged portion 31 which engages the fixed base plate at 11 by a pressfit. Holes 12 are provided for mounting the fixed base plate upon alarge table, floor, etc. The movable base plate 20 through opening 21,engages the portion 33 of the center spindle shown with a sliding fit.

A die spindle 40, having grooves 41, 42, 43 and 44 and a shoulder 45 isplaced upon the center spindle through center opening 49. It can be seenfrom FIG. 1 that the center spindle extends above the die spindle, theupper portion having threads 32. A combination retainer pivot and nut 46is then screwed onto the threads 32 to hold the die spindle 40 in place.

Mounted on the movable plate 20 is a roller assembly 50. This rollerassembly consists of an adjusting bolt 51 contoured at 52 to receive acrescent wrench or other device for rotation. The bolt is threaded at53.

The threaded portion 53 passes through divider blocks 60 throughopenings 63 and 64 therein. As shown in FIGS. 1 and 3, the dividerblocks are bolted tothe rotating base plate, into openings therein withbolts 61. The divider blocks are bolted at 62 to guide top containing agen eral elliptical opening 81 therein. There is a corresponding opening23 in the movable base plate.

The adjusting bolt unthreaded portion 54 also passes into a rollerfixture 70 shown in FIG. 4. This roller fixture comprises upper andlower plates 71 and 72 respectively, each having openings 73 and 74therein. These plates are bolted at 77 (or otherwise attached) to backblock 75. Circular end portion 54 of the adjusting bolt fits intoopening 76, but opening 76 is made sufficiently large that end portion54 may be easily removed therefrom.

Mounted between the plates 71 and 72 is a Wiper roller 90. A wiperroller pin 91 passes through the center of the wiper roller and into theelliptical openings 81 in the guide top and 23 in the movable baseplate. Clearance, for example, about two thousandths of an inch isprovided between the guide top 80 and the upper plate 71 and alsobetween the plate 20 and the lower roller fixture plate 72. Also,lubrication is generally provided so that the roller fixture assembly 70and wiper roller can move back and forth on the plate 20 by rotation ofadjusting bolt 50.

Mounted on the base plate 10 is a clamping block 100 shown in detail inFIG. 1. This clamping block is made in two halves, the stationary clampblock 101 and the movable clamp block 102. A socket head cap screw 103holds the fixed half 101 in place on the fixed base plate 10. Bolt-104passes through respectively openings 106 and 107. Both the halvescontain cooperating resessions 110 and 111 for processing inflatedstrip.

Follower block 120 shown in FIG. contains a plurality of grooves 121,122, 123 and 124. There is also provided a recess 125 to fit theshoulder 45 on the die spindle. If desired, both sides of the diespindle may be provided with grooves such as 121a, 122a, 123a and theblock reversed to accommodate the number of stop-weld patterns in thestrip. In either case, pins 126, 126a, for example, of. circular crosssection are provided to fit into the grooves, the length of the pinscorresponding to the length of the follower block. It should beemphasized, however, that the pins may be of any shape if matingsections are provided on die spindle 40 and follower block 120.

A retainer strap 130 is also provided, having an opening 131 whichopening allows placement of the strap upon the nut 46.

After placement of the nut 46 on the die spindle 40, the strap 130 maybe placed over shoulder 47 and resting on the die spindle and guide top80. The opening 131 provides a bearing surface during rotation aroundthe die spindle.

The retainer strap 130 has a second opening 132 through which passes alocking T 140. The T in engagement fits into an opening 82 in the guidetop 80,

Two adjustable screws 150 are also screwed into threaded holes 24 in themovable plate 20 to regulate the height of strip to be processed in theapparatus.

In operation, a piece of strip S which contains stopweld at appropriateplaces is fed through clamping block 100 and is placed upon theadjustable screws 150. The height of the adjustable screws 150 isadjusted so that the areas in the strip corresponding to desiredpassageways which contain stop-weld are in alignment with the pins 126on 126a or the follower block and the grooves 41-44 on the die spindle.The strip is clamped in the clamping block by tightening bolt 104 at apoint whereby the bend will occur at the die spindle at the desiredlength of the strip. One side of the strip contacts die spindle 40. Thefollower block 120 and pins are then brought into contact with the otherside of the strip. Also, at this point, the retainer strap 130 isengaged upon the die spindle nut 46. The locking T 140 is inserted intoopening 132 in the retainer strap and into the opening 82 in theguidetop.

The adjusting bolt 51 is rotated to urge the wiper block 90 into firmengagement with the follower block. For manual operation, a crescentwrench may be utilized to rotate the adjusting bolt 51, to insure firmengagement of the wiper roller 90 and follower block 120 with pins121-124.

At this point, the entire movable assembly is rotated with respect tothe fixed plate (clockwise in FIG. 1) around the die spindle 40 for atleast 25 and preferably 90 to 360. This, of course, bends the strip. Forexample, as indicated in FIG. 6, the strip 200 is bent 180". However, italso provides grooves 202 in the strip corresponding to the points onthe strip where passageways are to be inflated.

Upon inflation of the passageways, no kinking is observed in any sizeradiuses including radiuses below one inch. FIG. 7 shows the inflatedstrip, with passageways 302 corresponding to grooves 202 in FIG. 6,

After the strip has been bent, for example, into a serpentine pattern'by the bending just described, for many applications it is desirable tobraze or otherwise place fin material between the strip. Such finmaterial is shown at 310 in FIG. 7.

FIG. 8 shows an exemplary strip processing sequence.

4 The previously described bending takes place at schematically shownbending station 400. The strip will leave the bending station 400 andpass to theassembly station 410. At this point, the fin material 411 andend plates 413 and headers 414 are assembled. The fin material and/ orthe strip will contain a coating of brazing material so that when thestrip-fin units 412 are introduced into the furnace 420, which ismaintained at the temperature appropriate for the particular brazingalloy, strip material and fin material being processed, the fin materialis solidly brazed to the strip.

After the brazing operation, the articles are then moved on to theinflation station 430. At the inflation station at one end of the stripan inflation needle is introduced into the pattern of stop-weldmaterial, and clamped by means of hydraulic line 432. Fluid pressure bymeans of air line 431 which, for example, suppliesv water or air, isthen introduced into the opening and the passageway pattern is inflatedto form passageways corresponding to the passageways of stop-weldmaterial between the sheets. If desired, the inflated articles may bechecked for leaks in a water tank 440.

Inflation subsequent to the brazing operation provides very intimatecontact between the fin material and the strip so that the brazed finmaterial is in excellent heat exchange relation with the strip.

It is to be emphasized that the bending according to the presentinvention need not be used in connection with brazed fin applicationsonly. For example, the strip could be provided with fin area inaccordance with Keith application, Ser. No. 630,376, assigned to thesame assiguee as the present application.

It also is to be emphasized that the number of corresponding pins 126and grooves 41-44 may vary as desired. There have been shown four forpurposes of illustration but, if desired, one only, or a great manygrooves and corresponding pins may be provided in accordance with thenumber of passageways in this strip.

Other fastening methods, such as welding, could be used instead ofscrews.

Also, instead of a die spindle, a rubber pad could be used to cooperatewith pins 123 or other protrusion.

It is also to be emphasized instead of the follower block, the wiperroller could be contoured so as to contain the equivalent of pins 126 inthe follower block. Thus, with this construction, the follower blockwould be eliminated. Additionally, the embossing and bending could becarried out separately, but it is generally more convenient to carrythemv out simultaneously.

The bending operation of the present invention may be carried outcontinuously. This may be done in the following manner.

Strip is fed into the apparatus at a continuous intermittent rate aftera desired amount of strip has passed the clamping block. The clampingblock may be made to close automatically with an appropriateelectro-neumatic time sequence or, the bending and embossing could takeplace while the strip is moving. Likewise, either the follower block oran appropriately contoured wiper roller may be automatically moved intoengagement with the strip and the die spindle 40. Appropriateelectro-neumatic power would then rotate the movable plate around thedie spindle.

Such automatic control and time power sequence are well known to thoseskilled in the metal fabricating field. However, such automaticoperation would nonetheless produce bended strip free from kinks, whichis the essence of the present invention.

It is to be understood that the invention is not limited to theillustrations described and shown herein which are deemed to be merelyillustrative of the best modes of carrying out the invention, and whichare susceptible of modifications of form, size, arrangement of parts anddetail of operation, but rather is intended to encompass all suchmodifications which are within the spirit and scope of the invention asset forth in the appended claims.

What is claimed is:

1. In an elongated metal strip having a bend area and a pattern ofstop-weld material sandwiched within it, at least a portion of saidstop-weld pattern corresponding to at least one inflatable fluidpassageway, the improvement wherein: said strip contains at least onegroove in substantial alignment with said stop-weld patterncorresponding to said at least one inflatable fluid passageway, said atleast one groove extending intermediate the ends of said strip and saidat least one groove being in a bend area of said strip, wherein said atleast one groove extends in one direction only and is present prior toinflation of said fluid passageway.

2. In a strip as in claim 1 the further improvement wherein said stripis bent in said bend area at least about 25.

3. In a strip as in claim 1 the further improvement wherein said stripis bent in said bend area about 90 to 360.

4. In a strip as in claim 2 the further improvement wherein the bendradius of said bend is less than one inch. 5. In a strip as in claim 2the further improvement wherein said strip contains a plurality of saidinflatable fluid passageways and a corresponding plurality of saidgrooves.

References Cited UNITED STATES PATENTS 3,167,405 1/1965 Muije et al29-197 3,290,125 12/1966 Pryor 29183 999,390 8/1911 McMartin 72--3791,197,271 9/1916 Dieckmann 72-379 3,394,446 7/1968 Valyi 29-4709 X ALLENB. CURTIS, Primary Examiner US. Cl. X.R.

